Steam generator or water heater



May 14, 1940. 0 E. F. SPANNER 2.200.644

STEAM GENERATOR OR WATER HEATER Filed July 19, 1938 ooooooooooo 00000000 0 oooooooooo oo o Patented May 14, 1940 UNIT ST STEAM GENERATOR R WATER HEATER Edward Frank Spanner, Blackheath, London, England Application July 19, 1938, Serial No. 220,093

9 Claims.

This invention relates to steam generators or water heaters of vertical thimble tube type fired with coal, coke, gas, oil or any other usual fuel fed by hand or mechanical means.

The object of the invention is to reduce the height and cost of direct fired thimble tube boilers and also to improve the overall efiiciency of these boilers by maintaining a faster and more consistent speed of flow of the gases throughout the whole depth of the tube nest.

In thirnble tube boilers three factors are of great importance in securing high efficiency- (1) The length of the path the gas is forced to take through the tube nest in passing from furnace to flue.

(2) The total area of heating suriace'-and (3) The speed with which the gas actually passes the surfaces of the thimble tubes.

In thimble tube boilers of known practice it is usual to fit a multiplicity of rows of thimble tubes arranged in a simple staggered pattern. In boilers according to the present invention the diameter of the tube nest is increased, thus enab-ling more and longer thimble tubes to be fitted per row, and therefore the number of rows to be correspondingly reduced for the same total area of heating surface.

This is of definite advantage in improving the volume of the furnace and reducing the height and cost of the boiler, but it shortens the length of the direct path from bottom to top of the tube nest, and would normally result in loss of ethciency'.

The present invention however provides for fitting plain or stepped directional plates in the tube nest these forcing the products of combustion to take a much longer spiral path when passing from the furnace to the flue.

The invention also provides that the pitch of the spiralled directional plates shall be decreased towards the upper end of the tube nest so that the length of travel of the gases is increased as they get cooler, with the result that the speed of flow of the gas does not fall ofi as otherwise it would, thus maintaining good efiiciency throughout the full depth of the tube nest.

In order that the products of combustion shall not pass to the flue along the centre line of the tube nest, the invention provides a-heat resisting core hung axially along the centre line of the tube nest, together with means for raising and lowering same.

Further, in thimble tube boilers fitted for firing with coal or coke, it is important that the tube nest shall be kept clear of dust and soot and the invention provides that a soot-blower may be fitted below or above the tube nest, arranged for operating While the boiler is in service.

Finally the invention provides for the use of spiralled divisional plates or stepped directional plates in vertical steam generators or water heaters arranged to raise stem from two independent sources of heat, one source of heat being a direct-fired furnace surmounted by a thimble tube nest fitted with spirallel divisional plates or stepped directional plates, the other source of heat being a supply of hot waste gas directed into and around a watertube nest attached to'the inside of the outer shell so that both ends of the vertical watertubes fitted are open to the annular water and steam space, and so that a pasage is provided for hot exhaust gas between the outer shell and an inner circular plate joining the inside edges of the annular tube plates.

In the drawing Figure 1 is a vertical section through a large thimble tube boiler in accordance with the in vention. A water heater would be similar but with no steam space.

Figure 2 is a vertical section through a small thimble tube boiler in accordance with the invention. A Water heater would be similar but with no steam space. Figure 3 is a vertical section through a large thimble tube boiler in accordance with this invention and including also two watertube nests arranged to recover heat fromeiihaust gases. A water heater would be similar but with no steam space.

Figure 4 is an expansion of a typical tube plate showing spiralled directional plates.

Figure 5 is an expansion of a typical tube plate showing stepped directional plates at varying pitches.

In these figures, an annular water and steam space i, surrounds a cylindrical furnace plate 2, surmounted by a cylindrical tube plate 3 having expanded into it a multiplicity of rows of thimble tubes 4. In the centre of the tube nest is hung a heat-resisting deflector 5, which is adjustable in the large boiler by the suspension member 6. Plain or stepped spiral directional. plates 1 cause the gas to take a spiral path in passing upwards from the furnace 8 to the flue 9. Alternative positions for a steam soot-blower are shown at MA, MB, and NBC.

Figure 5 shows how decrease of pitch of the spiral flow is simply obtained by varying the width of the stepped directional plates.

In Figure 3, HA and B are circular watertube nests having vertical water-tubes open at each end to the space I and arranged to take discharges of exhaust gas from Diesel engines or the like, the gas entering and leaving the tube nests by the openings at IZA and I23.

I claim:-

1. An improved steam generator or water heater of vertical type comprising an annular water and steam space surrounding a cylindrical fiunace plate surmounted by a cylindrical tube plate, the tube plate having expanded into it inwardly projecting thimble tubes, a heat-resisting core hung axially along the centre line of the tube nest, and two or more sets of plain spiralled directional plates arranged between the tubes in the tube nest.

2. An improved steam generator or water heater of vertical type comprising an annular water and steam space surrounding a cylindrical furnace plate surmounted by a cylindrical tube plate, the tube plate having expanded into it inwardly projecting thimble tubes, a heat-resisting core hung axially along the centre line of the tube nest, and two or more sets of stepped directional plates arranged in spiral fashion between the tubes in the tube nest.

3. An improved steam generator or water heater of vertical type comprising an annular water and steam space surrounding a cylindrical furnace plate surmounted by a cylindrical tube plate, the tube plate having expanded into it inwardly projecting thimble tubes, a heat-resisting core hung axially along the centre line of the tube nest, together with means for raising or lowering same, and two or more sets of plain spiralled directional plates arranged between the tubes in the tube nest.

4. An improved steam generator or water heater of vertical type comprising an annular water and steam space surrounding a cylindrical furnace plate surmounted by a cylindrical tube plate, the tube plate having expanded into it inwardly projecting thimble tubes, a heat-resisting core hung axially along the centre line of the tube nest, together with means for raising or lowering same, and two or more sets of stepped directional plates arranged in spiral fashion between the tubes in the tube nest.

5. An improved steam generator or water heater of vertical type comprising an annular water and steam space surrounding a cylindrical furnace plate surmounted by a cylindrical tube plate, the tube plate having expanded into it inwardly projecting thimble tubes, a heat-resisting core hung axially along the centre line of the tube nest, togetherwith means for raising or lowering same, and two or more sets of stepped directional plates arranged in varying pitches between the tubes in the tube nest.

6. An improved steam generator or water heater of vertical type comprising an annular water and steam space surrounding a cylindrical furnace plate surmounted by a cylindrical tube plate, the tube plate having expanded into it inwardly projecting thimble tubes, a heat-resisting core hung axially along the centre line of the tube nest, together with means for raising or lowering same and for cleaning the tube nest by steam or air blast, and two or more sets of plain spiralled directional plates arranged between the tubes in the tube nest.

'7. An improved steam generator or water heater of vertical type comprising an annular water and steam space surrounding a cylindrical furnace plate surmounted by a cylindrical tube plate, the tube plate having expanded into it inwardly projecting thimble tubes, a heat-resisting core hung axially along the centre line of the tube nest, together with means for raising or lowering same and for cleaning the tube nest by steam or air blast, and two or more sets of stepped directional plates arranged in spiral fashion between the tubes in the tube nest.

8. An improved steam generator or water heater of vertical type comprising an annular water and steam space formed by an outer shell surrounding a cylindrical furnace plate surmounted by a cylindrical tube plate, the tube plate having expanded into it inwardly projecting thimble tubes, a heat-resisting core hung axially along the centre line of the tube nest, together with means for raising or lowering same and for cleaning the tube nest by steam or air blast, plain spiralled directional plates arranged between the tubes in the tube nest, the whole of the above forming a direct fired steam generator or water heater and having arranged in integral association therewith a waste gas steam generator or water heater comprising an annular water tube nest constructed of water tubes extending between vertically spaced parallel annular tube plates secured to the inside of the outer shell and cylinder means joining the inner edges of these annular tube plates so that an annular gas passage is formed between the outer shell and the cylinder joining the inner edges of the annular tube plates.

9. An improved steam generator or water heater of vertical type comprising an annular Water and steam space formed by an outer shell surrounding a cylindrical furnace plate surmounted by a cylindrical tube plate, the tube plate having expanded into it inwardly projecting thimble tubes, a heat-resisting core hung axially along the centre line of the tube nest, together with means for raising or lowering same and for cleaning the tube nest by steam or air blast, stepped directional plates arranged between the tubes in the tube nest, the whole of the above forming a direct fired steam generator or water heater and having arranged in integral association therewith a waste gas steam generator or water heater comprising an annular water tube nest constructed of water tubes extending between vertically spaced parallel annular tube plates secured to the inside of the outer shell and cylinder means joining the inner edges of these annular tube plates so that an annular gas passage is formed between the outer shell and the cylinder joining the inner edges of the annular tube plates.

EDWARD FRANK SPANNER. 

